from first principles PP-I-1

OP-I-3Activation of Oxygen on Microclusters of Silver Anchored on SiO 2 andAl 2 O 3 Surfaces. Embedded Cluster Scalar-Relativistic and PeriodicPseudopotential Density Functional CalculationsNasluzov V.A. 1 , Laletina S.S. 1 , Shor A.M. 1 , Shor. E.A. 1 , Rösch N. 21 Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, Russia2 Technische Universität München, Catalysis Research Center, Garching, Germanyv.nasluzov@yandex.ruIn continuation of our previous investigations of coinage metal microclusters on oxide supports,[1-4] we investigate structure, stability and reactivity of silver trimers and tetramers supported onα-alumina(0001) and model amorphous silica surfaces. Silver clusters of such small nuclearitysupported on alumina, in particular, are expected to be active centers of catalytic propyleneepoxidation [5] and NO selective catalytic reduction with hydrocarbons [6].We consider electron-deficient silver species bound to non-bridging oxygen centers(NBO), ≡Si–O• of MCM-41 silicalite wall and substituting protons of μ 3 -OH groups ofpartially hydroxylated alumina surface. Different structures of adsorption complexes of thesespecies with O 2 and NO molecules, which feature on top of silver atom and bridging to twosilver atoms, are compared. On alumina, bridging adsorption mode with respect to Ag atomand Al cations are considered as well. Reaction of surface NO oxidation connected withO-O bond splitting is considered as a probe for O 2 activation. Barrier heights for this reactionon alumina are consistent with the idea of moderate activation consistent with selectiveoxidation of reducing agents.References:[1] C. Inntam, L.V. Moskaleva, K.M. Neyman, V.A. Nasluzov, N. Rösch, Appl. Phys. A 82 (2006) 181.[2] V.A. Nasluzov, T.V. Shulimovich, A.M. Shor, V.I. Bukhtiyarov, N. Rosch, Phys. Status Solidi B 247(2010) 1023.[3] V.A. Nasluzov, T.V. Shulimovich, E.A. Ivanova-Shor, A.M. Shor, N. Rösch, Chem. Phys. Lett. 494(2010) 243.[4] A.M. Shor, E.A. Ivanova-Shor, S.M. Laletina, V.A. Nasluzov, N. Rösch, Surf. Sci. 604 (2010) 1705.[5] Y. Lei, F. Mehmood, S. Lee, J. Greeley, B. Lee, S. Seifert, R. E. Winans, J. W. Elam, R. J. Meyer,P. C. Redfern, D. Teschner, R. Schlögl, M. J. Pellin, L. A. Curtiss, S. Vajda, Science 328 (2010) 224.[6] J.P Breen, R. Burch, C. Hardacre, C. J. Hill, J. Phys. Chem. B 109 (2005) 4805.31